C. Bettanini

In situ measurements of the physical characteristics of Titan's environment

On the basis of previous ground-based and fly-by information, we knew that Titans atmosphere was mainly nitrogen, with some methane, but its temperature and pressure profiles were poorly constrained because of uncertainties in the detailed composition. The extent of atmospheric electricity (‘lightning’) was also hitherto unknown. Here we report the temperature and density profiles, as determined by the Huygens Atmospheric Structure Instrument (HASI), from an altitude of 1,400 km down to the surface. In the upper part of the atmosphere, the temperature and density were both higher than expected. There is a lower ionospheric layer between 140 km and 40 km, with electrical conductivity peaking near 60 km. We may also have seen the signature of lightning. At the surface, the temperature was 93.65 ± 0.25 K, and the pressure was 1,467 ± 1 hPa.

S.A.M., the Italian Martian Simulation Chamber

The Martian Environment Simulator (SAM “Simulatore di Ambiente Marziano”) is a interdisciplinary project of Astrobiology done at University of Padua. The research is aimed to the study of the survival of the microorganisms exposed to the “extreme” planetary environment. The facility has been designed in order to simulate Mars’ environmental conditions in terms of atmospheric pressure, temperature cycles and UV radiation dose. The bacterial cells, contained into dedicated capsules, will be exposed to thermal cycles simulating diurnal and seasonal Martian cycles. The metabolism of the different biological samples will be analysed at different phases of the experiment, to study their survival and eventual activity of protein synthesis (mortality, mutations and capability of DNA reparing). We describe the experimental facility and provide the perspectives of the biological experiments we will perform in order to provide hints on the possibility of life on Mars either autochthonous or imported from Earth.

Design and Validation of a Carbon-Fiber Collapsible Hinge for Space Applications: A Deployable Boom

This work presents an analysis and validation of a foldable boom actuated by tape-spring foldable elastic hinges for space applications. The analytical equations of tape-springs are described, extending the classical equations for isotropic materials to orthotropic carbon-fiber composite materials. The analytical equations which describe the buckling of the hinge have been implemented in a multibody simulation software where the hinge was modeled as a nonlinear elastic bushing and the boom as a rigid body. In the experimental phase, the boom was fabricated using a thin layer carbon-fiber composite tube, and the residual vibrations after deployment were experimentally tested with a triaxial accelerometer. A direct comparison of the simulation with the physical prototype pointed out the dangerous effect of higher order vibrations which are difficult to capture in simulation. We observed that while the vibrational spectra of simulations and experiments were compatible at low frequencies during deployment, a marked difference was observed at frequencies beyond 30 Hz. While difficult to model, higher order frequencies should be carefully accounted for in the design of self-deployable space structures. Indeed, if tape-springs are used as a self-locking mechanism, the higher vibrational modes could have enough energy to unlock the structure during operation.

The ExoMars DREAMS scientific data archive

DREAMS (Dust Characterisation, Risk Assessment, and Environment Analyser on the Martian Surface) is a payload accommodated on the Schiaparelli Entry and Descent Module (EDM) of ExoMars 2016, the ESA – Roscosmos mission to Mars successfully launched on 14 March 2016. The DREAMS data will be archived and distributed to the scientific community through the ESA’s Planetary Science Archive (PSA). All data shall be compliant with NASA’s Planetary Data System (PDS4) standards for formatting and labelling files. This paper summarizes the format and content of the DREAMS data products and associated metadata. The pipeline to convert the raw telemetries to the final products for the archive is sketched as well.

Accelerometers Data Elaboration during Separation and Atmosferic Descent of the Huygens Mock Up Probe in 2002 Stratospheric Balloon Launch Campaign

A mock up of the probe descending in Titan atmosphere as part of the Huygens Cassini Mission has been successfully launched and recovered on May 30th 2002 after a stratospheric balloon launch from the Italian Space Agency Base “Luigi Broglio” in Trapani, Sicily. To simulate Huygens mission at Titan, the probe has been lifted at 32 km altitude and then released to perform a 45 minutes parachute decelerated descent. An integrated data acquisition and instrument control system, based on PC architecture and soft-real-time application, sampled a total of 77 sensor channels during ascent, drift and descent phase. Among them probe hosts HASI accelerometer subsystem which has been developed mainly by Open University and contains one servo accelerometer sensitive to the mock-up spin axis and a three-axial piezoresistive accelerometer unit. This work analyses accelerometers data to investigate the dynamic behaviour of the probe after separation from the balloon, parachute opening and atmospheric descent. The work ends with a final study on temperature influence on piezo accelerometers measurements, where piezo unit values are checked with piezo temperature logs and servo accelerometer values in order to obtain an esteem of accelerometer unit performance with different temperature. HUYGENS MOCK UP PROBE The 1:1 scale mock-up of the Huygens probe has been completely developed at CISAS University of Padova. For a detailed description on probe mechanical and thermal configuration please refer to [1]. To be noted is that the overall external dimensions of the mock-up are 1304mm x 631 mm for a total weight close to 100 kg. Fig. 1 3D impression of Huygens mock up HASI ACC package is accommodated in the payload area in a position close to the centre of mass of the probe as shown in figure 2. HASSI ACC consists of: (1)One Servo ( highly sensitive ) accelerometer. (2) Three Piezo resistive ( PZR ) accelerometers, with one accelerometer mounted in each of the three orthogonal axes. (3) Two temperature sensors. The x-axis servo accelerometer’s output is conditioned and amplified by two noninverting amplifiers, one with gain of 1 and 54th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law 29 September 3 October 2003, Bremen, Germany IAC-03-I.2.05 Copyright